When video signals are handled by electronic devices, degradation of the video signals is inevitable. When video signals are processed in analog form, any operation on the video signal may add noise to the video signal. This may happen during mixing, filtering, and/or amplifying of the video signal. This may also happen during transmission of the signals through various media, for example, wireless transmission or cable transmission. Additionally, when analog video data is copied, successive generations of the video data may deteriorate more and more until, finally, the video may have too much noise to be viewable. When in a digital form, the video signals are much less susceptible to noise due to operations on the video signals. However, some deterioration of the digital video signals may still occur. For example, some video pixel bits may get corrupted, sometimes due to noise in the electronic circuitry and at other times by soft or hard memory failures. However, generally, there is no degradation from one generation to another when making copies of digital files. This is mainly due to the use of various methods to detect the errors. Upon detection of an error, the error can either be fixed if it is simple enough, or the file can be retransmitted or re-copied. Three examples of error detection schemes are parity bit, checksum and cyclical redundancy check (CRC). Some detected bit errors can be corrected by methods such as Hamming code.
In order to make transmission of a digital video file more efficient, the file is often compressed before transmitting and then decompressed when viewing the video. Reducing noise before compression can make compression of the video more efficient. This is because some video data compression algorithms, for example, MPEG (Moving Picture Experts Group) algorithms, encode differences between corresponding areas of multiple successive video frames. Therefore, spurious noise may introduce differences between video frames that may require additional data for encoding. Similarly, the decompression of video data may also introduce noise to the output if the video data has noise in it. Generally, a noise reduction scheme may reduce the artifacts of the lossy compression to make the video more visually pleasing. Sometimes, however, an overly aggressive compression scheme may result in a lossy compression where the decompressed data cannot maintain the original quality of the video data. Still, it may be desirable to have a means of reducing noise in digital video both before it is compressed and after it is decompressed.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.